This invention relates to a hand held tool and more particularly to an attachment to an air hammer for removing a bolt from a fixture.
The removal of a bolt or rod from a fixture holding the bolt or rod is a common task in maintaining vehicles such as large trucks, off-road vehicles and trailers, as well as construction, farming and mining equipment. This task is often very time consuming and keeps the vehicle or equipment from being more productive.
The removal of bolts or rods is often made more difficult by corrosion of the material and by the use of rubber bushings which grip the bolt or rod and keep it from being easily removed. This is particularly true for those components associated with the suspension systems of vehicles. For example, the assembly that attaches a leaf spring of a heavy truck or trailer axle to a shackle fixture on the frame of the truck or trailer often has a rubber grommet. This grommet grips the assembly to remove any possibility of a loose fit (non-compliant) spring attachment. Removal of the bolts securing this assembly is very difficult and due to corrosion and/or wear can take 3 to 4 hours to remove a single bolt using standard means.
The invention of the pneumatically activated hammer or drill tool has eliminated much of the physical effort in driving or impacting an object. However, even these tools have their limits as they are heavy and alignment with an object such as a bolt or rod to be driven is only partially achieved presenting a difficult problem. Also, shock loads from the driving energy is not properly absorbed. In U.S. Pat. No. 1,213,970 the spud end of a shank of a hammer drill fits into a hole in a socket such that a head of the shank engages the head of a spike. The socket guides the spud and slides up on two rods against the compression of two soft springs at the end of the driving operation. At the point of contact between the head of the driving spud and the fixture, the end of the spike approaches the forward end of the socket. Two additional stiff springs and two additional nuts maintain the two rods as well as the socket displaced from a tool holder on the drill hammer. This spike holder requires a number of spring and rod components and the socket does not contact the fixture receiving the spike until the end of the driving operation.
A similar device is disclosed in U.S. Pat. No. 2,272,760 where a sleeve is attached to the end of a driving device stem to loosely receive the head of a railroad spike. The guiding element sleeve is permanently attached to the end of a stem. A compression spring is positioned within an enlarged portion of the sleeve. As the head of the spike approaches the railroad tie the sleeve abuts the rail flange and compresses the spring. The sleeve does not abut the rail until the end of the driving operation.
A nail driver disclosed in U.S. Pat. No. 2,890,455 has a sleeve supported by two springs from a retaining member placed against a tool housing or collar of the pneumatic hammer. A housing spring has a spacing of the coils (pace) such that no compression can occur. The other spring fits inside the housing spring around a driving member and abuts the sleeve and the retaining member. The housing spring retains the stem portion or driving bit from falling out of the tool and the other spring allows the sleeve to be telescoped by compressing this inner spring. The housing spring cannot be stretched and substituted for the other spring due to the constant wear that would require replacement of the entire housing spring, as disclosed in the patent. Two springs, the retaining member and the sleeve are required with this nail driver, and no requirement to contact the fixture receiving the nail is disclosed.
According to U.S. Pat. No. 4,646,852 there is provided a hand tool in the form of a pneumatic activated mallet. A mallet head is reciprocally mounted in a housing and a spring biases the mallet head away from the driver. A push force on a nose piece on the mallet will compress the spring and allow the driver to contact the mallet head. This hand tool does not suggest a device to retain an article being driven.
The art does not solve the need for a low cost attachment that can be used as an alignment an shock absorbing device for removing a bolt or rod from a fixture.
Accordingly, an object of the invention is to provide a simple low cost attachment for an air hammer to be used to remove a bolt or rod from a fixture when the holding power of the fixture requires a relatively long driving distance;
Another object of the invention is to provide an alignment and shock absorbing attachment for an pneumatic power tool that will facilitate removal of a bolt or rod from a fixture;
A further object of the invention is to reduce the time it takes to remove a bolt being held by corrosion and/or wear that continuously holds the bolt during the entire removal process.